Exercise-Provoked Wide-Complex Tachycardia and Extreme Duke Score: Orthodromic Reciprocating Tachycardia Unmasked by Electrophysiology Study.

BACKGROUND

Wide-complex tachycardia during exercise testing is treated as ventricular tachycardia until proven otherwise, yet supraventricular tachycardia with aberrancy can mimic this presentation with distinct implications.

CASE SUMMARY: A 44-year-old man developed sustained wide-complex tachycardia with left bundle branch block morphology during stress-test recovery, with lateral ST depression, a Duke Treadmill Score of -25.3, and troponin elevation. Angiography and cardiac magnetic resonance excluded obstructive and structural heart disease. Electrophysiology study demonstrated orthodromic reciprocating tachycardia via a concealed left posterior accessory pathway with left bundle branch block aberrancy. Radiofrequency ablation eliminated accessory pathway conduction, and a postablation exercise test induced no arrhythmia and was negative for ischemia.

DISCUSSION: Arrhythmia-related ST changes limited the reliability of the Duke Treadmill Score in this setting. Systematic evaluation with angiography, cardiac magnetic resonance, and electrophysiology study established the diagnosis and enabled curative ablation.